1. Field of the Invention
This invention relates to systems for use in preventing damage to structures in case of earthquake and, in particular, to an aseismic system for structure foundations.
2. Description of the Prior Art
According to statistics, an average of twenty-five severe earthquakes occur each year causing loss of lives and property. These areas in which earthquakes occur are known as "seismic zones" or "geological faults" and cover a large portion of the surface of the earth. Up to now man has not been able to control or arrest seismic activity, and for this reason it is imperative that buildings be constructed with such occurences in mind particularly in the "seismic zones." In this regard, there are two schools of thought, firstly, anti-seismic structures and, secondly, aseismic structures. In the case of anti-seismic structures, they are constructed to resist the horizontal forces that push it laterally during an earthquake. In the case of aseismic structures, they are not subject to these movements and thus do not require reinforcement to resist them.
Presently, there exists an aseismic system based on orthogonally positioned rollers which, by combining their displacements, permit the building to move in any direction. This system requires a double foundation: one to transmit the building loads to the rollers and the other to distribute the building loads to the ground. The loads must be concentrated because the two foundations must be tangential to the rollers.